yes I clean the cache frequently, seems like the web was very heavy and the browser cant handle. The sand clock just keep turning, till the browser closes, and all sms are gone.
I have a "not so old" backup, so at least Ill take back a couple of sms..but I dont like this type of bugs, even if its low memory, it could delete other data

what is your file free from options > status? the memory issue is to keep the device from locking up. unlike other devices when the blackberry runs out of memory, it attempts to keep working by deleting sms/mms/call logs and old calendar appointments.

Thanks for the info, didn´t know that "strange" politic of delete data, when runs out of memory. Ill try to free up memory, and make backup frequently, cause you never know when you are going into a very heavy webpage